Frans Pop is a confirmed suicide (more details). Significantly, he resigned the night before Debian Day for the purpose of suicide and he wrote multiple grievances.
Ian Murdock, Debian's founder, is a confirmed suicide. (more details).
Lucy Wayland: the coroner's report states that the cause of death was an accident and that Wayland was alone and suffering from alcohol dependency. (more details).
Jens Schmalzing died in Germany where the coroner's report is kept secret. Without access to the official cause of death, there is no distinction between an accident and a suicide. Schmalzing's death involved falling from a rooftop. (more details).
Thiemo Seufer died in Germany where the coroner's report is kept secret. Without access to the official cause of death, there is no distinction between an accident and a suicide. Furthermore, if a vehicle accident involved lack of sleep, excessive working hours, the coroner's findings in such matters are secret. (more details).
William Lee Irwin III was reported to be having a crisis and living in a homeless shelter. He subsequently vanished and all the discussion about him stopped. More details may have been shared on IRC. We do not officially know if he is still alive. (more details).
Chris Rutter died crossing the road. News reports suggest the driver was not at fault. Records show Rutter was often doing his unpaid Debian work up to 3am while in his first year of undergraduate study, depriving him of sleep. (more details).
Manuel Estrada Sainz and Andres Garcia died in a car accident driving home from a conference on a Sunday night. They had almost completed the 660km journey when they had the accident in what appear to be sleep-deprived conditions. (more details (Estrada)) and (more details (Garcia)).
Adrian von Bidder died from a heart attack around the time the local group in Switzerland began preparing their bid to host DebConf13. (more details).
Abraham Raji died at DebConf23. He drowned while other members of the group were kayaking. People abandoned the search and his body had to be recovered by the local residents. (more details)